An automated means for collecting meter data involves a fixed wireless network. Devices such as, for example, repeaters and gateways are permanently affixed on rooftops and pole-tops and strategically positioned to receive data from enhanced meters fitted with radio-transmitters. Typically, these transmitters operate in the 902-928 MHz range and employ Frequency Hopping Spread Spectrum (FHSS) technology to spread the transmitted energy over a large portion of the available bandwidth. Data is transmitted from the meters to the repeaters and gateways and ultimately communicated to a central location.
With the increased sophistication of meter reading techniques has come the corresponding sophistication of billing techniques. For example, energy meters may be operated as either a “demand” meter or as a “time-of-use” (TOU) meter. TOU meters allow a power company to provide greater differentiation by which the energy is billed. Energy metered during peak hours will be billed differently than electrical energy billed during non-peak hours. Also, demand meters allow for a billing charge based on the maximum amount of power consumed in a given period of time (e.g., 15 minutes). As a result, keeping track of time in the meter, both relative and absolute, has become more significant.
However, devices without clocks (e.g., water and gas meters) traditionally have not been able to provide TOU metering. TOU metering would be beneficial in the context of water and gas metering because TOU pricing helps distribute demand more evenly over a period of time. In the context of electricity, electrical energy is generated and reserve capacity not easily stored. While water and gas supplies are not generated, they must be pressurized and reserve capacity must be pumped to storage containers. Demand on the water and gas systems in the form of usage at endpoints results in a drop in system-wide pressure, which must be overcome using pumps. Since these pumps are almost always electrical, water usage is tied, though somewhat indirectly, to electricity usage. Demand on the water supply system is therefore related to demand on the electrical system and some of the same reasons to evenly distribute demand, or move demand into off-peak times, exist with water and gas systems as with electricity systems.
In addition, as water supplies in urban areas become more and more limited, municipalities may look for ways to limit water use (e.g., by using punitive pricing or restricting use outright). Examples of usage restrictions include daily restrictions on commercial and residential irrigation users, e.g., odd/even watering days, prohibited watering days, etc. TOU water metering will offer additional pricing and enforcement flexibility. For example, some municipalities have implemented limits on irrigation use by limiting irrigation to particular days of the week. This is typically enforced by visual inspection, but is fundamentally a time of use issue. Therefore, with TOU water metering, municipalities could penalize usage outside of certain time windows, for example mid-day (which is less efficient than late evening or early morning) or off-day irrigation, with higher pricing.
Water theft is another area of increasing concern for not only municipalities, but also for the individual consumers that may be affected. It would be desirable to monitor usage behavior via the data collection system. By comparing collected interval data against predefined usage profiles and schedules, suspect usage can be identified and the appropriate authorities automatically notified. Future visual inspections can thus be more appropriately targeted to suspected violators.
Therefore, there is a need to provide efficient techniques for providing TOU billing and data collection in relative time, clock-less metering devices, as well as a mechanism to detect fraudulent consumption.